We will evaluate the association between growth failures (GF) in children, and sleep disordered breathing (SDB) characterized by snoring, apnea, and mouth-breathing. Adenotonsillar hypertrophy is the primary factor leading to SDB in children. Tonsillectomy and adenoidectomy (T&A) is curative in 80% of cases. As an intervention specifically for SDB, children undergoing T&As show, as a corollary benefit, catch-up growth. Data from small, case series of referred children suggest that SDB may increase the risk of GF, but this has never been evaluated in a longitudinal, population-based study. We will analyze data on SDB and GF in the Avon Longitudinal Study of Parents and Children (ALSPAC), a prospective, population-based cohort study in the U.K. ALSPAC is amongst the largest, most well-delineated child cohorts in the world. Preliminary ALSPAC data find smaller height increases from 6- 42 months of age in children who snored at 6 months (p<.05), and;from 30-42 months of age in children who breathed through their mouth at 18 months (p<.03), and those with reported apnea at 18 months of age (p<.02). To our knowledge, ours is the first study designed to examine the impact of SDB upon poor growth over time. Primary Aims: (entire cohort) 1) To Characterize Sleep Disordered Breathing (SDB) Symptoms in Childhood We will: a) measure the prevalence, severity, and persistence of SDB symptoms, and;b) delineate trends in the natural and treatment history of SDB from infancy through pre-puberty. 2) To Determine the Association Between SDB Symptoms &Growth We will assess: a) whether the prevalence, severity, and persistence of SDB symptoms is associated with GF, and;b) whether such associations are mediated by or are independent of factors such as: early growth patterns, feeding habits, energy intake, T&A surgery, and;family demographics. Secondary Aim: (sub-sample of cohort) 3) To Determine Associations Between SDB Symptoms, Dietary Intake, Growth Biomarkers, &Growth We will analyze: a) the association between plasma insulin-like growth factors, leptin levels, dietary intake, and SDB, and;b) the effects of these biomarkers and SDB, and their interactions on growth. PUBLIC HEALTH RELEVANCE: ALSPAC provides an unprecedented opportunity to examine sleep disordered breathing (SDB) and growth throughout childhood, and evaluate evidence of causality. ALSPAC follows an inception cohort of 13,000+ children since 1992. Validated measures and multiple data sources (e.g., exams, surveys, and health records) will permit reasonably valid conclusions. The project's international multidisciplinary team includes expertise in: biostatistics, endocrinology, epidemiology, nutrition, otolaryngology, pediatrics, and pulmonology/sleep medicine. Few pediatric primary care providers screen for SDB, and 50% are unaware of its potential link to growth failure (GF). Neither they, nor sub-specialists in pediatric GF routinely include upper airway obstruction in their differential diagnosis of GF. If SDB has a significant temporal association with GF in our longitudinal, multivariable analysis, there are strong clinical practice implications for the screening, referral, and treatment of children with GF.